This invention is an improvement over the type B-31 continuous mixer and unloader sold commercially by the Allen-Sherman-Hoff Company of Wynnewood, Pennsylvania. Material such as fly ash may have a particle size of the order of one micron up to about 100 mesh. The purpose of the mixer and unloader is to moisten dry material such as fly ash during removal from a storage bin to eliminate dust pollution during loading and transport of the material. Due to the small size of fly ash particles, they are in a fluidized state and flow like a liquid.
In connection with handling of materials such as fly ash, there is a phenomenon known as incipient aeration. There is effectively no aeration provided for in the storage bin. When a particle starts to drop, it stirs up the air through which it drops, causing more particles to drop which in turn stir up more air thereby creating what is known as rat holing. Even if a large piece of material should fall off the side wall of the supply of material, it will flow through the rat hole rather than plug up the rat hole. There results an avalanche of uncontrollable flow in combination with fluidized particles which are not properly moistened by the above-mentioned mixer.
In the above-mentioned mixer, there is provided a doctor blade within the upper portion of the drum. Such doctor blades have heretofore been located and designed so the drier, lighter, or relatively unwetted mixture only would accumulate on it and drop back down into the continuously freshly mixed portion without exposing it directly to or through a water spray. This has resulted in varying performance because the properly wetted mixture continues on and out of the operation carrying dry portions with it.
This invention is directed to a continuous mixer and dust conditioner wherein a support is provided for a conveyor. A drum circumscribes the support and conveyor. The conveyor communicates with the drum interior.
A plurality of discrete stationary blades are provided in the drum adjacent to but spaced from the ID of the drum. A plurality of nozzles are supported within the drum adjacent to said blades. The blades are curved so as to direct material and any fluidized fines radially inwardly from the ID of the drum into the spray from said nozzles.
Because of the specific weight of the fluidized fine particles, the centrifugal action of the drum has little or no influence on such particles. The blades direct the fluidized particles into the spray from the nozzles thereby increasing the specific weight of the fluidized particles whereby they will then be subjected to centrifugal action and can be removed from the drum as part of a slurry.
It is an object of the present invention to provide a continuous mixer and dust conditioner which materially reduces or eliminates disadvantages of prior art devices subject to incipient aeration.
It is another object of the present invention to provide a continuous mixer and dust conditioner which includes a plurality of curved blades arranged to direct material into a nozzle spray to thereby increase the specific weight whereby it can be subject to centrifugal action.
It is another object of the present invention to provide a continuous mixer and dust conditioner which is more efficient than prior art devices in connection with fluidized material such as fly ash.
Other objects will appear hereinafter.